Is it possible to call Javascript's onsubmit event programatically on a form?

In Ruby on Rails, I'm attempting to update the innerHTML of a div tag using the form_remote_tag helper. This update happens whenever an associated select tag receives an onchange event. The problem is, <select onchange="this.form.submit();">; doesn't work. Nor does document.forms[0].submit(). The only way to get the onsubmit code generated in the form_remote_tag to execute is to create a hidden submit button, and invoke the click method on the button from the select tag. Here's a working ERb partial example.

I want to axe the invisible submit button, but using a straight form.submit appears to not work. So, I need some way to call the form's onsubmit event code.

Update: Orion Edwards solution would work if there wasn't a return(false); generated by Rails. I'm not sure which is worse though, sending a phantom click to an invisible submit button or calling eval on the getAttribute('onsubmit') call after removing the return call with a javascript string replacement!

In theory, something like eval ('function(){' + code + '}()'); could work (that syntax fails though). Even if that did work, it would still be sort of ghetto to be calling an eval through a select onchange. Another solution would be to somehow get Rails to inject the onsubmit code into the onchange field of the select tag, but I'm not sure if there's a way to do that. ActionView has link_to_remote, but there's no obvious helper to generate the same code in the onchange field.